class Solution {
public:
    int minDistance(string word1, string word2) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int n = word1.length();
        int m = word2.length();

        if (n == 0) {
            return m;
        } else if (m == 0) {
            return n;
        }
        vector<vector<int> > dp(n + 1, vector<int>(m + 1));
        for (int i = 0; i <= n; ++i) {
            dp[i][0] = i;
        }
        for (int j = 0; j <= m; ++j) {
            dp[0][j] = j;
        }
        for (int i = 1; i <= n; ++i) {
            for (int j = 1; j <= m; ++j) {
                if (word1[i - 1] == word2[j - 1]) {
                    dp[i][j] = dp[i - 1][j - 1];
                } else {
                    dp[i][j] = min(dp[i - 1][j], min(dp[i][j - 1], dp[i - 1][j - 1])) + 1;

                }
            }
        }
        return dp[n][m];
    }
};
